The specific aims of the proposed three-year renewal are to pursue several lines of inquiry, each investigating a pivotal target behavior that has important implications for improving the treatment of autistic children. Each pivotal target area appears especially important because of its impact on numerous other collateral behaviors in the children's functioning. These areas include: (A) investigating the parameters and effects of observational learning on acquisition of appropriate behaviors and reduction of inappropriate behaviors; (B) further investigating the relationship between the children's reduced responsivity to the learning environment and their learning handicaps and to assess possible collateral effects of increasing responsivity; (C) developing procedures that hold promise for enhancing generalization and maintenance of behavior change; (D) identifying procedures to reduce interfering inappropriate behaviors (self-stimulation); (E) investigating procedures to improve social responsiveness; and (F) to obtain measures of the social significance of the interventions derived from the above studies.